Trevor is a hero from Pokémon X and Pokémon Y and a hero from the Pokémon anime.
After Ash and his friends saw the complete Kanto starters trio, Trevor came down from the stairs, exhausted from chasing Charmander. Like in the games, his goal as a Trainer is to meet every Pokémon in the Pokédex as stated during his introduction. Later, he had a battle with Clemont and his Chespin. The battle didn't continue after Chespin was accidentally burned by Charmander.
In Day Three Blockbusters!, Trevor fished a Wailord during the fishing competition which gave his team the win. He was also in a PokéVision video along with his fellow teammates but did not win.
In Battling Into the Hall of Fame!, he had a Triple Battle with Ash, Serena, and Clemont. Despite putting up a great fight, Trevor was the first one to get defeated and then Shauna and Tierno got defeated afterwards.
Trevor appeared again in Performing with Fiery Charm! where he watched Serena competing in the Dendemille Town Pokémon Showcase along with Tierno and Shauna.
Trevor appeared again in A Legendary Photo Op!, where he met up with Ash and his friends and sought out, and succeeded in taking a picture of the Legendary Moltres.
Trevor appeared briefly in Tag Team Inspiration!, where he was seen taking a picture of a wild Lairon.